park light goes off when you open door
Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=96543
Printed Date: May 12, 2025 at 7:51 PM
Topic: park light goes off when you open door
Posted By: demented
Subject: park light goes off when you open door
Date Posted: August 21, 2007 at 12:18 PM
I want to hook up a relay system that turns my park lights off when I open my door after I forgot them on. Any help on a diagram/suggestion.
Replies:
Posted By: hotwaterwizard
Date Posted: August 21, 2007 at 10:49 PM
You need to latch the lights and unlatch them with the pin switch. It would be easier if you use a seperate Alarm switch for this purpose.  ------------- John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !
Posted By: demented
Date Posted: August 23, 2007 at 12:42 PM
^^^ That will not work in my application. sorry I was thinking more like, when the ignition is it will power a relay to supply the light switch (latched) So the lights can be turned on and off using the light switch once the ignition came on and latched. But if I foret my lights on, when i switch off my ignition, the lights will still be on...and only go off after I open my door. Also, if the car is running and I open my door, the lights should remain on if they are on.
Posted By: dualsport
Date Posted: August 23, 2007 at 9:19 PM
It'd be easy to do with a digital logic gate to control your relay, if you can't find a relay only solution. Depends how comfortable you are with a bit of electronics work, but it's pretty simple if you've done any. A CD4011 chip. a BS170 transistor, a sprinkling of diodes, and your relay is all it would need.
Posted By: hotwaterwizard
Date Posted: August 23, 2007 at 10:07 PM
Here is the same circuit modified  ------------- John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !
Posted By: dualsport
Date Posted: August 24, 2007 at 1:11 AM
Here's another way to go, assuming the door switch closes to ground when the door is opened.
Posted By: hotwaterwizard
Date Posted: August 24, 2007 at 8:16 AM
Just curiousDualsport, Why use a Static sensitive MOSFET when a Transistor will do the job without having to use wrist ground straps and a shielded soldering iron durring assembly. Back in the day before Digital Voice Recorders and all that stuff I used a Cassete player with a Tape from an answering machine to verbaly remind me when I left the lights on in my own voice. When I opened the door it used a relay to power the cassete. I would only come on when the lights were on and the door opened. ------------- John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !
Posted By: hotwaterwizard
Date Posted: August 24, 2007 at 8:31 AM
This circuit could be used a relay AND Circuit. 
------------- John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !
Posted By: dualsport
Date Posted: August 24, 2007 at 8:54 AM
A regular transistor can be used with no problem here; I just like the BS170 in general because it operates on voltage rather than current, so the input impedance can be ignored when using it in timing circuits, and no concern about proper biasing.
The logic gate draws negligible power when on standby, which is what you'd want for something that can operate with the ignition turned off. If someone isn't comfortable working with electronics, then a relays-only setup would be good. Otherwise, a single extra relay costs more than all the electronic components this would need.
Posted By: dualsport
Date Posted: August 24, 2007 at 9:00 AM
Lot of cars go bong bong bong when the lights are left on when exiting the car.
I'd consider using a piezoelectric buzzer hooked up under the hood to the parking lights and ignition power, so that whenever the lights are on with the ignition off, it'll sound off (polarity sensitive so it doesn't come on with ignition on and lights off).
As you walk away from the car, you'll hear it. No problems with possibly failing relays, and it'll alert you to turn things off. That'd be a $2.99 solution using a buzzer and a diode.
Posted By: demented
Date Posted: August 27, 2007 at 6:49 AM
These are what I came up with: 
With a pulse input:
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